Sodium Carbonate → 6-(-2-chloropyridin-3-yl)-1-methyl-1H-indazole

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Reaction Steps

Analogous to the preparation of 5-(2-chloropyridin-3-yl)-1H-indazole,6-(-2-chloropyridin-3-yl)-1-methyl-1H-indazole was prepared by heating the mixture of 6-bromo-1-methyl-1H-indazole (2.0 g, 9.5 mmol), 2-chloro-3-pyridine boronic acid pinacol ester (2.2 g, 9.4 mmol), Pd(PPh3)4 (0.54 g, 0.46 mmol) and 2M aq. Na2CO3 (14 mL, 28 mmol) in 1,4-dioxane (75 mL) under argon atmosphere for 12 h. Upon extractive work-up as discussed in the preparation of 5-(2-chloropyridin-3-yl)-1H-indazole with CH2Cl2 and purification of the concentrate by flash silica gel column chromatography (Combiflash® companion System® with RediSep® silica gel column 40 g, 30-50% EtOAC/hexanes eluting solvent gradient upon dry loading the concentrate absorbed on silica gel) provided 6-(-2-chloropyridin-3-yl)-1-methyl-1H-indazole as a white solid (1.8 g, 77%). 1H NMR (DMSO-d6): δ 8.45 (dd, 1H, J=1.7 and 4.7 Hz), 8.09 (s, 1H), 7.94 (dd, 1H, J=2.0 and 7.6 Hz), 7.82 (d, 1H, J=8.5 Hz), 7.74 (s, 1H), 7.54 (dd, 1H, J=4.7 and 7.6 Hz),7.22 (d, 1H, J=8.5 Hz), 4.06 (s, 3H).LCMS: rt 6.80 min (A), purity 97%, MS (m/e) 244 (MH+)

Provenance & Evidence